Design, prototyping and construction

Transcription

1 Chapter 11 Design, prototyping and construction 1

2 Overview Prototyping and construction Conceptual design Physical design Generating prototypes Support for design 2

3 Prototyping and construction What is a prototype? Why prototype? Different kinds of prototyping low fidelity high fidelity Compromises in prototyping vertical horizontal Construction 3

4 What is a prototype? In other design fields a prototype is a small-scale model: a miniature car a miniature building or town the example here comes from a 3D printer 4

5 What is a prototype? In interaction design it can be (among other things): a series of screen sketches a storyboard, i.e. a cartoon-like series of scenes a Powerpoint slide show a video simulating the use of a system a lump of wood (e.g. PalmPilot) a cardboard mock-up a piece of software with limited functionality written in the target language or in another language 5

6 Why prototype? Evaluation and feedback are central to interaction design Stakeholders can see, hold, interact with a prototype more easily than a document or a drawing Team members can communicate effectively You can test out ideas for yourself It encourages reflection: very important aspect of design Prototypes answer questions, and support designers in choosing between alternatives 6

7 Filtering dimensions of prototyping 7

8 Manifestation dimensions of prototyping 8

9 What to prototype? Technical issues Work flow, task design Screen layouts and information display Difficult, controversial, critical areas 9

10 Low-fidelity Prototyping Uses a medium which is unlike the final medium, e.g. paper, cardboard Is quick, cheap and easily changed Examples: sketches of screens, task sequences, etc Post-it notes storyboards Wizard-of-Oz 10

11 Storyboards Often used with scenarios, bringing more detail, and a chance to role play It is a series of sketches showing how a user might progress through a task using the device Used early in design 11

12 Sketching Sketching is important to low-fidelity prototyping Don t be inhibited about drawing ability. Practice simple symbols 12

13 Card-based prototypes Index cards (3 X 5 inches) Each card represents one screen or part of screen Often used in website development 13

14 Wizard-of-Oz prototyping The user thinks they are interacting with a computer, but a developer is responding to output rather than the system. Usually done early in design to understand users expectations What is wrong with this approach? User >Blurb blurb >Do this >Why? 14

15 High-fidelity prototyping Uses materials that you would expect to be in the final product. Prototype looks more like the final system than a low-fidelity version. For a high-fidelity software prototype common environments include Macromedia Director, Visual Basic, and Smalltalk. Danger that users think they have a full system.see compromises 15

16 Compromises in prototyping All prototypes involve compromises For software-based prototyping maybe there is a slow response? sketchy icons? limited functionality? Two common types of compromise horizontal : provide a wide range of functions, but with little detail vertical : provide a lot of detail for only a few functions Compromises in prototypes mustn t be ignored. Product needs engineering 16

17 Construction Taking the prototypes (or learning from them) and creating a whole Quality must be attended to: usability (of course), reliability, robustness, maintainability, integrity, portability, efficiency, etc Product must be engineered Evolutionary prototyping Throw-away prototyping 17

18 Conceptual design: from requirements to design Transform user requirements/needs into a conceptual model a description of the proposed system in terms of a set of integrated ideas and concepts about what it should do, behave and look like, that will be understandable by the users in the manner intended Don t move to a solution too quickly. Iterate, iterate, iterate Consider alternatives: prototyping helps 18

19 Is there a suitable metaphor? Interface metaphors combine familiar knowledge with new knowledge in a way that will help the user understand the product. Three steps: understand functionality, identify potential problem areas, generate metaphors Evaluate metaphors: How much structure does it provide? How much is relevant to the problem? Is it easy to represent? Will the audience understand it? How extensible is it? 19

20 Considering interaction types Which interaction type? How the user invokes actions Instructing, conversing, manipulating or exploring Do different interface types provide insight? WIMP, shareable, augmented reality, etc 20

21 Expanding the conceptual model What functions will the product perform? What will the product do and what will the human do (task allocation)? How are the functions related to each other? Sequential or parallel? Categorisations, e.g. all actions related to telephone memory storage What information needs to be available? What data is required to perform the task? How is this data to be transformed by the system? 21

22 Using scenarios in conceptual design Express proposed or imagined situations Used throughout design in various ways scripts for user evaluation of prototypes concrete examples of tasks as a means of co-operation across professional boundaries Plus and minus scenarios to explore extreme cases 22

23 Generate storyboard from scenario 23

24 Generate card-based prototype from use case 24

25 Support for design Patterns for interaction design individual patterns pattern languages pattern libraries Open source systems and components Tools and environments 25

26 Summary Different kinds of prototyping are used for different purposes and at different stages Prototypes answer questions, so prototype appropriately Construction: the final product must be engineered appropriately Conceptual design (the first step of design) Consider interaction types and interface types to prompt creativity Storyboards can be generated from scenarios Card-based prototypes can be generated from use 26 cases